Aquarium Systems VisiTherm Mini Heater 25W is a mini submersible heater for aquariums and aqua-terrariums. Made of extra hard polymer and filled with epoxy resin. Unbreakable. Thermal protection that switches off the heating when it is taken out of the water. Temperature pre-set to 26°C. Operating mode light LED. Waterproof double insulation. Overheat protection. Reinforde plastic.